Addresses the use of the area of contamination (AOC) concept during RCRA cleanups, and the relationship of an AOC to a corrective action management unit (CAMU). An AOC refers to a discrete area of generally dispersed contamination. Discusses the regulatory status of the CAMU rule in relation to the Hazardous Waste Identification Rule (HWIR)-Media and litigation (SEE ALSO: 63 FR 65873; 11/30/98). Also discusses the definition of placement.